Eight-under par won it for In Gee Chun in 2015 at Lancaster Country Club. On Thursday at CordeValle, Mirim Lee took the outright lead on day one of the 2016 US Women’s Open with an eight-under par 64. She holds a three-stroke lead ahead of Minjee Lee, Cristie Kerr and Amy Yang.

Cold and cloudy conditions greeted players Thursday morning but as skies cleared in the morning and the sun broke through, the course changed, allowing players to hit the ball farther and go at some of the difficult pin placements they wouldn’t otherwise have been able to attack. But the change only seemed to favor those in the morning, with the exception of Amy Yang who carded the low round of the afternoon with a five-under-par 67 to pull within three-strokes of Lee.

Mirim Lee started her day on the back nine with a bogey on her first hole of the day but recovered with back-to-back birdies and closed with seven more to finish her day atop the leaderboard. Lee says her driver was the key to going low on Thursday, making for what she called an “easy day.”

Lee seems to thrive in major championship environments, posting one of two top-10’s this season at the KPMG Women’s PGA Championship where she finished in a share of fourth. Her round on Thursday was the best opening round in a US Women’s Open since Kelli Kuehne in 1999 at Old Waverly Golf Club and one shy of the record set by Helen Alfredsson in 1994 who opened with a 63 at Indianwood Golf and Country Club. Lee also joins a short list of players to tie the largest 18-hole lead in the history of the Championship at three-strokes. Lee’s 10 birdies are the most in one round in the US Women’s Open, breaking the previous record of nine.

Mirim Lee played alongside Cristie Kerr who shot a five-under-par 67 and said she expects the USGA to toughen-up the course on Friday after her playing partner went so low on day one. Kerr has a new PXG driver in her bag this week, which she credited for her low round on Thursday.

‘When you’re struggling to hit fairways, I can’t blame everything on the club, obviously, but when you’re struggling to hit fairways, it makes the game a lot harder. And then the mental game gets off of it, it’s a whole process like that,’ said Kerr. ‘But I knew when I found the driver this week that it just felt so much like my old driver and we found the right combination and even if I missed a little bit I could feel what I did wrong, I could feel the difference. Like I said, I’m just happy that we worked it out.’

After winning twice in 2015 including the season ending CME Group Tour Championship, Kerr has struggled this season and is looking to pick up just her second top-10 of the season this week at CordeValle. But, the world number 21 knows what it takes to play well in this Championship, capturing the 2007 US Women’s Open at Pine Needles Lodge and Golf Club and posting an additional six top-10’s in this event.

Minjee Lee also carded a 67 on Thursday to finish the day in a share of second at five-under-par, but felt she could have gone even lower if she had been able to get her putter rolling.

‘I hit really good shots into the first couple of holes and I missed the putts — I missed my putts,’ Minjee Lee told the media. ‘I felt like I was really solid, like my iron play was really solid. And if I missed my drives, it was sort of just on the first cut or maybe just in the rough. So I thought I striked the ball really well today. I gave myself a lot of opportunities for birdie.’

Minjee Lee had four birdies, an eagle and one bogey in her opening round.

Two-time US Women’s Open runner-up Amy Yang moved into a share of second with Minjee Lee and Cristie Kerr by posting the low round of the afternoon with a five-under-par 67, matching her opening score in this event last year where she finished one behind champion In Gee Chun. Yang skipped last week’s Cambia Portland Classic to return to her home in Orlando to work with her instructor Tony Ziegler in order to best prepared for what this year’s championship would present her and hopefully finish with a win this time around.

‘I have like tendency using too much my wrist, hitting it through the ball. So I have a little bit of tendency hitting it stronger draw out there. So we worked on it, and it’s helping really good,’ Yang told the media. ‘I’m not try to play too aggressive out here because the course setup is hard. It’s getting drier every day. So my goal is to — not to make many mistakes throughout the week.’

Anna Nordqvist hit every green in regulation on Thursday, a first in the history of the US Women’s Open. The feat earned her a share of fifth at four-under-par along with Brittany Lang and Kelly Tan. Lang said she made an adjustment midway through her round when the course conditions began to change and opened her stance slightly.

‘Everything changed a little bit tournament time, with nerves and adrenaline a little bit. And I wasn’t hitting them as solid,’ Lang said. ‘I just knew if I dropped that left foot back, it’s a simple fix, it gives me more room and I automatically start hitting them really pure.’

Lang has three top-10 finishes in the US Women’s Open, including a runner-up finish in her first start in 2005.

Sydnee Michaels, Moriya Jutanugarn and Eun Hee Ji sit in a share of eighth at three-under-par, five-strokes back of Mirim Lee.

Defending champion In Gee Chun carded her highest round in this Championship with a one-over-par 73 on Thursday. The 1998 U.S. Women’s Open champion, Se Ri Pak, is making her last competitive start in the States this week and also sits at one-over-par. The grouping of the top-ranked players in the field – number one Lydia Ko, number two Brooke Henderson and number three Lexi Thompson – finished at a collective seven-over-par on day one.